A semiconductor package can be a metal, plastic, glass, or ceramic casing containing one or more semiconductor electronic components, also referred to as dies or integrated circuits (ICs). The package provides protection against impact and corrosion, as well as environmental factors, such as moisture, oxidation, heat, and contaminants. Electrical contacts or leads emminate from the package and are connected to other devices and/or to an intermediary substrate, or directly to a circuit board. The package may have as few as two leads or contacts for devices such as diodes, or have several hundred leads or contacts in the case of a microprocessor.
The semiconductor package can be a special purpose self-contained device, which can be mounted to a printed circuit board (PCB) or a printed wiring board (PWB) of an end product. ICs can be connected to a substrate in a variety of layouts, as well as stacked in multiple layers. In addition, packages can be mounted upon other packages to form a package-on-package device. The semiconductor package can also be mounted to a flexible circuit, such as a tape.
User products are becoming more complicated with several features and functions. In addition, many user products are becoming smaller. As a result, manufacturers are utilizing packaging alternatives as a way of achieving more features and functions in a smaller area or volume.
Semiconductor packages can be completely manufactured at a wafer level, including fabricating the individual ICs, multiple level metallization, encapsulation, and attachment of solder balls (or other conductive interconnects) in a grid array configuration. The completed wafer is then singulated, i.e. separated into individual packaged ICs.
A common method of singulation is wafer sawing along saw streets between the ICs. The wafer saw completely cuts through the individual packaged ICs. However, sawing can damage the area near the cut, especially the dielectric layers and the metallization layers. In addition, the die coating can become delaminated from the metallization layers, due to damage of the seal ring during singulation. As a result, delamination can penetrate inside the seal ring of the die and cause eventual failure of the IC. Additional processing can also cause the delamination to continue propagating. Other types of singulation include stealth dicing and plasma dicing.